358win,
Sorry I couldn't include every medium-rate powder in the tests, but as pointed out during my discussion of Vihatvouri N150, the pressure curve of double-based powders (especially newer ones) can be VERY different than the single-based IMR4895 the Garand was designed around. This can result in different pressures on the operating rod, even though the powder APPEARS to be about the same burn-rate as IMR4895. And IMR4166 is a new double-based powder, without much info on how it might affect Garands. If you want to experiment with IMR4166, feel free, but I was not about to risk damaging the op-rod on my friend's rifle by freelancing in that direction.
For those who haven't read the article, aftermarket gas-ports were explained and discussed. But the article was about loading for original Garands without them.
